Aliexpress
Here are coupons that you can use.
Latest price update (UTC time):
Banggood
Banggood warehouse is located in China.
Link: Banggood product page
Coupon (29.74 USD): MVC8SPRING
Coupon (30.07 USD): 2203ActiesNL
Coupon (30.39 USD): BG00c906
(CouponsFromChina.com tip: just apply this code in your cart after clicking “Proceed to checkout”. Click to copy code and open shop)
Exclusive Allowance Coupons: https://bit.ly/3xWgD9k
Old coupons (from the oldest to the newest): BG4d9120, 00c906, ADMITAD2212, 2022ACTIESNL, Tabby20, BG1efeb0
(I don’t think these’re gonna work, but you can try ’em out anyway)
Price history and price alert
Check out price history chart (for all/most countries) for Dog Training Collar 500m.
Price records source(s): Banggood
Click on image to enlarge. 
You can set price alert (for Banggood).